Question

Из пункта А одновременно в одном направлении выехали два мотоциклиста: один со скоростью 75 км/ч, другой со скоростью 60 км/ч. Через 20 минут за ними из пункта А выехал третий мотоциклист. Найдите скорость третьего мотоциклиста, если известно, что он догнал первого мотоциклиста на 1 час 42 минуты позже, чем второго.

Answer 1

S - расстояние между 1 и 2 после того как догнал 1-го 3-ий
s/1.25-s/1=102
4s/5-s=102
0.8s-s=102
-0.2s=102
|s|=20.4 км

v - скорость 3-го
v=s/t=20.4/102=0.2 км/мин = 30 км/ч

Answer 2

Problem Analysis

We are given that two motorcyclists leave point A simultaneously in the same direction. The first motorcyclist has a speed of 75 km/h, and the second motorcyclist has a speed of 60 km/h. After 20 minutes, a third motorcyclist leaves point A and catches up to the first motorcyclist 1 hour and 42 minutes later than the second motorcyclist. We need to find the speed of the third motorcyclist.

Solution

Let's assume that the third motorcyclist's speed is x km/h.

To find the speed of the third motorcyclist, we can use the formula:

Distance = Speed × Time

Let's calculate the distances traveled by the first and second motorcyclists after 20 minutes:

- First motorcyclist: Distance = Speed × Time = 75 km/h × (20 minutes / 60 minutes/hour) = 25 km - Second motorcyclist: Distance = Speed × Time = 60 km/h × (20 minutes / 60 minutes/hour) = 20 km

Now, let's calculate the time it takes for the third motorcyclist to catch up to the first motorcyclist:

- Time = 1 hour and 42 minutes = 1 hour + 42 minutes = 1.7 hours

Since the third motorcyclist catches up to the first motorcyclist, the distance traveled by the third motorcyclist is equal to the distance traveled by the first motorcyclist